1. Field of the Invention
The present invention relates to wireless communications, and more specifically, to a method of performing wireless communication using multiple directional antennas.
2. Discussion of the Related Art
As wired/wireless communication technology grows, various communication devices may happen to access a wide band communication network anytime and anywhere on land. However, despite a very old communication type, maritime communication systems are relatively slow in growth. Such maritime communication systems are mostly limited as providing voice-oriented communication services plus simple text transmission services.
It is difficult to establish the infrastructure for wired communication on the sea. Maritime communications cannot but rely on wireless communication-oriented services and make use of communication based on MF (Medium Frequency), HF (High Frequency), and VHF (Very High Frequency) bands due to limited arrival distance of wireless frequency. Long-distance sailing vessels rely on high-price satellite communications for telecommunication.
In the maritime communication field where such maritime communication systems apply, the GMDSS (Global Maritime Distress and Safety system) has been introduced since back in 1990.
The GMDSS which uses digital and satellite communication technology for safety of human beings on the sea allows a ship, although wrecked anywhere on the sea, to ask for rescue another nearby ship or an on-land rescue organization in a quick and exact manner. Further, the GMDSS allows for proper reception of information regarding sailing safety from the land.
Further, the IMO (International Maritime Organization) is now establishing a strategy for developing the E-navigation.
The E-navigation is a scheme that may collect, integrate, exchange, express, and analyzes various types of information with a ship by utilizing the AIS (Automatic Identification System) that enables real-time transmission/reception of a diversity of information related to characteristics, freight, and voyage of the ship. By utilizing this, a maritime ITS (International Transportation System) may be established that may encompass data and multimedia.
Further, telecommunication technology such as WLAN (Wireless Local Area Network), WiMAX (World Interoperability for Microwave Access) is considered for renewing maritime communication for ports and ships, and in recent years, the VHF band-based AIS associated with satellite is emerging as a maritime infra communication network.